Migrated from Outlook 2011 (14.2.5) to MacMail (version 6.2)
It seems that my end of year email clean-up binge and archving corrupted my outlook identity such that it couldn't rebuild. I have my data pretty well backed up so I didn't stand to lose any data. Nonetheless, the failure to rebuild left me a little less confident in Outlook. I couple of other folks had this happen and did lose some data. So I started a new identity and moved my email archives over to the new identity. Obviously the server data migrated over without a problem when setting up the new identity.
To note: this site has some good information when you run into issues: http://www.officeformachelp.com/2012/05/how-to-move-your-data-to-a-new-identity/
Office is a great tool but it is quite frankly overkill for what I need for email etc. as I use omnifocus for my task manager and the integration to Mail is better than Outlook. Much like data portability in via text files, I wanted to get my email data a little more portable. As I searched, I found only sketchy recommendations for migrating my Outlook data .olm file to mac mail and it seemed like I shouldn't need a 3rd party solution to make this work.
It turns out it is dead easy to do. You simply drag your archive folder to another folder on your Mac and you'll get a .mbox file of the folder that you can easily import into mac mail. I suggest you test it out yourself with a small number of emails. It took about 10 - 15 mins. to export 2 - 3000 email folders. I couldn't drag the archive to the desktop, I had to drag it to a folder on my desktop to make it work.
I don't want to get into a position where my email client can shut me down for 2 - 3 hours to get back up and running again. So I'm going to manage a short term archive (I use the pile of records in a folder approach to email with smart folders) on the server for portability and have redundant archives of my older email in outlook and Mac Mail. Mail goes belly up and I use Outlook or Outlook goes belly up and I use Mail
However, day to day I'm going to use Mail, iCal, and Address Book with Address Book being the clear weak link in the chain.
For ease of folks who may also be looking to switch from Outlook 2011 for Mac to Mac Mail, simply drag your archives to a folder on your Mac and import the .mbox folder into mac mail. Since I'm a corporate stooge, everything else goes over via the cloud exchange server.